Many people suffer from an inability to control urinary function, i.e., urinary incontinence. Different muscles, nerves, organs and conduits within the urinary tract cooperate to collect, store and release urine. A variety of disorders may compromise urinary tract performance and contribute to incontinence. Many of the disorders may be associated with aging, injury or illness. For example, aging can often result in weakened sphincter muscles, which cause incontinence, or weakened bladder muscles, which prevent complete emptying. Some patients also may suffer from nerve disorders that prevent proper triggering and operation of the bladder or sphincter muscles.
Fecal incontinence is the inability to control bowel function. Fecal incontinence may be attributable to many physiological conditions, such as damage to the muscles of the rectum (e.g., the anal internal or external sphincters), nerve damage, loss of storage capacity within the rectum, and pelvic floor dysfunction.
Electrical stimulation of nerves may provide an effective therapy for a variety of disorders, including urinary incontinence and fecal incontinence. For example, an implantable neurostimulator can deliver electrical stimulation to the sacral nerve to induce sphincter constriction and thereby close or maintain closure of the urethra at the bladder neck. In addition, electrical stimulation of the bladder wall may enhance pelvic floor muscle tone and assist fluid retention in the bladder or voiding fluid from the bladder.
In current clinical practice to minimally implant a sacral stimulation lead, the procedure starts with a kit comprising a needle and a dilator that are particularly adapted to enable introduction of a neurostimulation lead into a foramen to locate a distal lead electrode(s) in operative relation to a sacral nerve. The needle is adapted to be inserted through an entry point of the skin or a skin incision posterior to the sacrum. The needle is guided along an insertion path into a foramen to locate at least a distal portion thereof extending alongside a sacral nerve. A proximal portion of the needle extends from the entry point away from the patient's skin. The dilator is inserted over the needle proximal end and advanced distally over the needle to dilate the insertion path to that of the dilator diameter. The needle is then withdrawn through the dilator body lumen. The stimulation lead can now be advanced through the dilator body lumen to locate the lead electrode into operative relation with the sacral nerve. The dilator is then withdrawn over or removed from the stimulation lead body.
The above practice requires multiple steps and disposable components in a kit to implant the stimulation lead. This takes time and creates extra trauma around the stimulation lead. Therefore, in the current invention, a simplified implant method, and a modified stimulation lead and kit are described.